Is Mariza currently the unified world champion singer, across all disciplines?

I recently bought Mariza's 'Concerto Em Lisboa' CD and, for good measure, rented the DVD as well. The thing that struck me was, as usual, the bleedin' obvious. She's a fantastic singer. No second takes, no overdubbing. Totally immersed in the emotion of each song. At one point she even breaks down during the last song, O Gente Da Minha Terra, as she's so overcome with its emotion (and, having watched the DVD, it's no affectation, it's genuine). She didn't even do her party piece of singing without any microphone (which, having seen her live a couple of years ago, is truly impressive).

Is Mariza the undisputed world champion singer of our time? The Aretha of the 2000s? Or are there any other contenders who could go 12 rounds with her?